SES to Slack

This is an AWS Lambda function to forward mails from SES to Slack, based on the Serverless framework.

How it works

Mail Server
↓ SMTP
AWS SES
↓ Publish
AWS SNS
↓ Subscribe
AWS Lambda
↓ HTTP(S)
Slack Incoming Webhook

Getting Started

Deploy a Lambda function.

# Setup credentials
npm run serverless -- config credentials -p aws -k IAM_KEY -s IAM_SECRET

# Deploy
npm install
npm run deploy

Open the AWS Management Console and do following steps:

1. Open Lambda and Check ARN of the function, like arn:aws:lambda:ap-northeast-1:***:function:ses-to-slack-dev-handle.
2. Add an environment variable on the function:
   • WEBHOOK: URL of Slack Incoming Webhook (Mandatory)
   • WEBHOOK_USERNAME: Username for Incoming Webhook request (Optional)
   • WEBHOOK_ICON_EMOJI: Icon for Incoming Webhook request (Optional)
   • WEBHOOK_HOST_HEADER: Host header for Incoming Webhook request (Optional)
3. Open SNS and create a topic.
4. Create a subscription on the topic:
   • Protocol: AWS Lambda.
   • Endpoint: ARN of the Lambda function.
5. Open SES and make sure your domain has been verified.
6. Create a rule set with the following action:
   • SNS topic: ARN of the SNS topic.
   • Encoding: UTF-8

Sending to Mattermost

Mattermost is a Slack alternative. You can send mails to a Mattermost channel as well.

1. Create an Incoming Webhook on a Mattermost team.
2. Set the WEBHOOK environment variable.

If the instance is protected by the security group, you can send mails via VPC. For example,

Mail Server
↓ SMTP
AWS SES
↓ Publish
AWS SNS
↓ Subscribe
AWS Lambda
↓ ENI
↓ VPC
↓ ENI
AWS EC2

If a reverse proxy exists and requires Host header, you can specify the WEBHOOK_HOST_HEADER environment variable.

Caveat

SNS can receive mails that are 150kB or less. Larger mails will bounce.

Contributions

Feel free to open an issue or pull request.